#include<bits/stdc++.h>
using namespace std;
 
#define sd(mark) scanf("%d",&mark)
#define ss(mark) scanf("%s",&mark)
#define sl(mark) scanf("%lld",&mark)
#define debug(mark) printf("check%d\n",mark)
#define clr(mark) memset(mark,0,sizeof(mark))
#define F first
#define S second
#define MP make_pair
#define PB push_back
#define ll long long
#define LIM 100000
#define N 15
set<int> setx,sety;
int x[N],y[N];
int main()
{
	int q,n,i;
	sd(q);
	while(q--)
	{
		sd(n);
		int minx = LIM,maxx = -LIM,miny = LIM,maxy = -LIM; 
		for(i=0;i<n;++i)
		{
			sd(x[i]);sd(y[i]);
			minx=min(minx,x[i]);
			maxx=max(maxx,x[i]);
			miny=min(miny,y[i]);
			maxy=max(maxy,y[i]);
		}

		for(i=0;i<n;++i)
			if((x[i] != minx && x[i] != maxx) && (y[i] != miny && y[i] != maxy))
				break;
		if(i<n)
			printf("NO\n");
		else
			printf("YES\n");
	}
}